Scientists enhance '3D polymer' method

A team of scientists from the Technological Institute for Superhard and Novel Carbon Materials (TISNCM) in Troitsk, Russia has developed a novel method for synthesising the ultra-hard material fullerite.

Ultra-hard fullerite, which exceeds the hardness of diamond, is a polymer composed of fullerenes - spherical molecules consisting of 60 carbon atoms.

“The discovery will create a new research area in materials science

Lead author Mikhail Popov

According to research, the carbon spheres within fullerite can be arranged in a variety of ways, and the material’s hardness largely depends on just how interconnected they are.

In the ultra-hard fullerite discovered by scientists at TISNCM, C60 molecules are interconnected by covalent bonds in all directions - a material which scientists have dubbed a ’three-dimensional polymer’.

Unfortunately, synthesising this material on an industrial scale is not yet possible due to the high pressure required for the reaction to begin, the researchers said.

Formation of the three-dimensional polymer begins at a pressure of 13 gigapascals (GPa). However, modern equipment cannot provide such pressure on a large scale.

Fortunately, the TISNCM team have shown that adding carbon disulfide to the initial mixture of reagents can accelerate fullerite synthesis.

Though carbon disulfide is an end product, in this instance it acts as an accelerator. Using carbon disulfide, the formation of the superhard material is more probable, even if the pressure is lower and amounts to 8GPa.

“The discovery will create a new research area in materials science because it substantially reduces the pressure required for synthesis and allows for manufacturing the material and its derivatives on an industrial scale,” said Mikhail Popov, leading author of the research.